Display system with virtual image distance adjustment and corrective lenses

ABSTRACT

A head-mounted device may have a display that displays computer-generated content for a user. The head-mounted device may have an optical system that directs the computer-generated image towards eye boxes for viewing by a user. The optical system may be a see-through optical system that allows the user to view a real-world object through the optical system while receiving the computer-generated image or the optical system may include a non-removable lens and a removable vision correction lens through which an opaque display is viewable. The optical system may include a removable lens. The removable lens may serve as a custom vision correction lens to correct for a user&#39;s vision defects. The optical system may have a projection bias lens that places computer-generated content at one or more desired virtual image distances and a corresponding compensation bias lens.

This application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 16/713,877, filed Dec. 13, 2019, which claims thebenefit of U.S. Provisional Patent Application No. 62/792,730, filedJan. 15, 2019. The disclosures of these applications are herebyincorporated by reference herein in their entireties.

BACKGROUND

This relates generally to electronic devices and, more particularly, towearable electronic device systems.

Electronic devices are sometimes configured to be worn by users. Forexample, head-mounted devices are provided with head-mounted structuresthat allow the devices to be worn on users' heads. Head-mounted devicesmay include optical systems with lenses. The lenses allow displays inthe devices to present visual content to users.

Some users of head-mounted devices have visual defects such as myopia,hyperopia, astigmatism, or presbyopia. It can be challenging to ensurethat an optical system in a head-mounted device displayscomputer-generated content satisfactorily and provides an acceptableviewing experience for users with visual defects. If care is not taken,it may be difficult or impossible for a user with visual defects tofocus properly on content that is being displayed or content mayotherwise not be displayed as desired.

SUMMARY

A head-mounted device may have a display that displayscomputer-generated content for a user. The head-mounted device may havean optical system that directs the computer-generated content towardseye boxes for viewing by a user.

In one illustrative configuration, the optical system may include anon-removable lens and a removable lens through which an opaque displayis viewable. The removable lens may serve as a vision correction lensand may have radially increasing lens power to compensate for fieldcurvature in the optical system.

In another illustrative configuration, the optical system may be asee-through optical system that allows the user to view a real-worldobject through the optical system while receiving the computer-generatedimage. This type of system may have a waveguide with an output couplerinterposed between at least first and second lenses. The display mayprovide an image to the waveguide. The output coupler may couple theimage from the waveguide towards the eye box through the first lens. Thefirst lens may be a projection bias lens that adjusts virtual imagedistance for the image. The second lens may be a correspondingcompensation bias lens that compensates for the first lens and allowsthe user to view the real-world object normally. If desired, the firstlens or a removable third lens in the optical system may serve as avision correction lens.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative electronic device suchas a head-mounted display device in accordance with an embodiment.

FIG. 2 is a top view of an illustrative head-mounted device inaccordance with an embodiment.

FIG. 3 is a diagram of an illustrative display and associated opticalsystem with removable lens structures in accordance with an embodiment.

FIG. 4 is a diagram of a user's field of view showing how differentportions of the field of view may be provided with virtual image contentat different virtual image distances in accordance with an embodiment.

FIGS. 5, 6, and 7 are graphs showing how lens power may vary as afunction of position within lenses in an optical system in accordancewith embodiments.

FIGS. 8, 9, and 10 are diagrams of illustrative displays and associatedoptical systems in accordance with embodiments.

FIG. 11 is a side view of an illustrative head-mounted device with anopaque (non-see-through) display and optical system in accordance withan embodiment.

FIG. 12 is a diagram of an illustrative lens for the head-mounted deviceof FIG. 11 in accordance with an embodiment.

FIG. 13 is a diagram of an illustrative display and optical system for adevice such as the head-mounted device of FIG. 11 in accordance with anembodiment.

DETAILED DESCRIPTION

Electronic devices may include displays and other components forpresenting content to users. The electronic devices may be wearableelectronic devices. A wearable electronic device such as a head-mounteddevice may have head-mounted support structures that allow thehead-mounted device to be worn on a user's head.

A head-mounted device may contain a display formed from one or moredisplay devices for displaying visual content to a user. A lens systemmay be used to allow the user to focus on the display and view thevisual content. To ensure that a wide range of users are able to clearlyfocus on the display and view visual content, the head-mounted devicemay receive removable supplemental lenses. The supplemental lenses mayaddress the visual defects of users that are not otherwise addressed bythe lens system. For example, a user with astigmatism may be providedwith removable supplemental lenses that correct for astigmatism. Whenthis user desires to view content with the head-mounted device, thesupplemental lenses may be installed within the head-mounted device tohelp correct for the user's astigmatism. With one illustrativearrangement, the supplemental lenses may be coupled to the head-mountedsupport structures using magnets or other removable fasteners that placethe supplemental lenses in alignment with non-removable lenses in thedevice.

A schematic diagram of an illustrative system that may use removablelenses is shown in FIG. 1 . As shown in FIG. 1 , system 8 may includeone or more electronic devices such as electronic device 10. Theelectronic devices of system 8 may include computers, cellulartelephones, head-mounted devices, wristwatch devices, and otherelectronic devices. Configurations in which electronic device 10 is ahead-mounted device are sometimes described herein as an example.

As shown in FIG. 1 , electronic devices such as electronic device 10 mayhave control circuitry 12. Control circuitry 12 may include storage andprocessing circuitry for controlling the operation of device 10.Circuitry 12 may include storage such as hard disk drive storage,nonvolatile memory (e.g., electrically-programmable-read-only memoryconfigured to form a solid-state drive), volatile memory (e.g., staticor dynamic random-access-memory), etc. Processing circuitry in controlcircuitry 12 may be based on one or more microprocessors,microcontrollers, digital signal processors, baseband processors, powermanagement units, audio chips, graphics processing units, applicationspecific integrated circuits, and other integrated circuits. Softwarecode may be stored on storage in circuitry 12 and run on processingcircuitry in circuitry 12 to implement control operations for device 10(e.g., data gathering operations, operations involving the adjustment ofthe components of device 10 using control signals, etc.). Controlcircuitry 12 may include wired and wireless communications circuitry.For example, control circuitry 12 may include radio-frequencytransceiver circuitry such as cellular telephone transceiver circuitry,wireless local area network (WiFi®) transceiver circuitry, millimeterwave transceiver circuitry, and/or other wireless communicationscircuitry.

During operation, the communications circuitry of the devices in system8 (e.g., the communications circuitry of control circuitry 12 of device10), may be used to support communication between the electronicdevices. For example, one electronic device may transmit video and/oraudio data to another electronic device in system 8. Electronic devicesin system 8 may use wired and/or wireless communications circuitry tocommunicate through one or more communications networks (e.g., theinternet, local area networks, etc.). The communications circuitry maybe used to allow data to be received by device 10 from externalequipment (e.g., a tethered computer, a portable device such as ahandheld device or laptop computer, online computing equipment such as aremote server or other remote computing equipment, or other electricalequipment) and/or to provide data to external equipment.

Device 10 may include input-output devices 22. Input-output devices 22may be used to allow a user to provide device 10 with user input.Input-output devices 22 may also be used to gather information on theenvironment in which device 10 is operating. Output components indevices 22 may allow device 10 to provide a user with output and may beused to communicate with external electrical equipment.

As shown in FIG. 1 , input-output devices 22 may include one or moredisplays such as display(s) 14. In some configurations, display 14 ofdevice 10 includes left and right display devices (e.g., left and rightcomponents such as left and right scanning mirror display devices,liquid-crystal-on-silicon display devices, digital mirror devices, orother reflective display devices, left and right display panels based onlight-emitting diode pixel arrays (e.g., organic light-emitting displaypanels or display devices based on pixel arrays formed from crystallinesemiconductor light-emitting diode dies), liquid crystal display devicespanels, and/or or other left and right display devices in alignment withthe user's left and right eyes, respectively. In other configurations,display 14 includes a single display panel that extends across both eyesor uses other arrangements in which content is provided with a singlepixel array.

Display 14 is used to display visual content for a user of device 10.The content that is presented on display 14 may include virtual objectsand other content that is provided to display 14 by control circuitry 12and may sometimes be referred to as computer-generated content.Computer-generated content may be displayed in the absence of real-worldcontent or may be combined with real-world content. In someconfigurations, a real-world image may be captured by a camera (e.g., aforward-facing camera) so that computer-generated content may beelectronically overlaid on portions of the real-world image (e.g., whendevice 10 is a pair of virtual reality goggles with an opaque display).In other configurations, an optical coupling system may be used to allowcomputer-generated content to be optically overlaid on top of areal-world image. As an example, device 10 may have a see-throughdisplay system that provides a computer-generated image to a userthrough a beam splitter, prism, holographic coupler, or other opticalcoupler while allowing the user to view real-world objects through theoptical coupler.

Input-output circuitry 22 may include sensors 16. Sensors 16 mayinclude, for example, three-dimensional sensors (e.g., three-dimensionalimage sensors such as structured light sensors that emit beams of lightand that use two-dimensional digital image sensors to gather image datafor three-dimensional images from light spots that are produced when atarget is illuminated by the beams of light, binocular three-dimensionalimage sensors that gather three-dimensional images using two or morecameras in a binocular imaging arrangement, three-dimensional lidar(light detection and ranging) sensors, three-dimensional radio-frequencysensors, or other sensors that gather three-dimensional image data),cameras (e.g., infrared and/or visible digital image sensors), gazetracking sensors (e.g., a gaze tracking system based on an image sensorand, if desired, a light source that emits one or more beams of lightthat are tracked using the image sensor after reflecting from a user'seyes), touch sensors, buttons, capacitive proximity sensors, light-based(optical) proximity sensors, other proximity sensors, force sensors,sensors such as contact sensors based on switches, gas sensors, pressuresensors, moisture sensors, magnetic sensors, audio sensors(microphones), ambient light sensors, microphones for gathering voicecommands and other audio input, sensors that are configured to gatherinformation on motion, position, and/or orientation (e.g.,accelerometers, gyroscopes, compasses, and/or inertial measurement unitsthat include all of these sensors or a subset of one or two of thesesensors), and/or other sensors.

User input and other information may be gathered using sensors and otherinput devices in input-output devices 22. If desired, input-outputdevices 22 may include other devices 24 such as haptic output devices(e.g., vibrating components), light-emitting diodes and other lightsources, speakers such as ear speakers for producing audio output, andother electrical components. Device 10 may include circuits forreceiving wireless power, circuits for transmitting power wirelessly toother devices, batteries and other energy storage devices (e.g.,capacitors), joysticks, buttons, and/or other components.

Electronic device 10 may have housing structures (e.g., housing walls,straps, etc.), as shown by illustrative support structures 26 of FIG. 1. In configurations in which electronic device 10 is a head-mounteddevice (e.g., a pair of glasses, goggles, a helmet, a hat, etc.),support structures 26 may include head-mounted support structures (e.g.,a helmet housing, head straps, temples in a pair of eyeglasses, gogglehousing structures, and/or other head-mounted structures). Thehead-mounted support structures may be configured to be worn on a headof a user during operation of device 10 and may support display(s) 14,sensors 16, other components 24, other input-output devices 22, andcontrol circuitry 12.

FIG. 2 is a top view of electronic device 10 in an illustrativeconfiguration in which electronic device 10 is a head-mounted device. Asshown in FIG. 2 , electronic device 10 may include support structures(see, e.g., support structures 26 of FIG. 1 ) that are used in housingthe components of device 10 and mounting device 10 onto a user's head.These support structures may include, for example, structures that formhousing walls and other structures for a main unit (e.g., supportstructures 26-2) and additional structures such as straps, temples, orother supplemental support structures (e.g., support structures 26-1)that help to hold the main unit and the components in the main unit on auser's face so that the user's eyes are located within eye boxes 60.

Display 14 may include left and right display portions (e.g., sometimesreferred to as left and right displays, left and right display devices,left and right display components, or left and right pixel arrays). Anoptical system for device 10 may be formed from couplers 84 (sometimesreferred to as input couplers), waveguides 86, optical couplers such asoutput couplers 88, and lenses 80 and 82. A user with eyes located ineye boxes 60 may view real-world objects through the optical systemwhile viewing overlaid computer-generated content from display 14.

As shown in FIG. 2 , the left portion of display 14 may be used tocreate an image for a left-hand eye box 60 (e.g., a location where aleft-hand image is viewed by a user's left eye). The right portion ofdisplay 14 may be used to create an image for a right-hand eye box 60(e.g., a location where a right-hand image is viewed by a user's righteye). In the configuration of FIG. 2 , the left and right portions ofdisplay 14 may be formed by respective left and right display devices(e.g., digital mirror devices, liquid-crystal-on-silicon devices,scanning microelectromechanical systems mirror devices, other reflectivedisplay devices, or other displays). In arrangements in which display 14is opaque and blocks real-world images from direct viewing by the user,display 14 may be an organic light-emitting diode display, a liquidcrystal display, or other display and the optical coupler formed fromwaveguides 86 and output couplers 88 may be omitted.

In the see-through display arrangement of FIG. 2 , optical couplers 84(e.g., prisms, holograms, etc.) may be used to couple respective leftand right images from the left and right display portions intorespective left and right waveguides 86. The images may be guided withinwaveguides 86 in accordance with the principal of total internalreflection. In this way, the left and right images may be transportedfrom the left and right sides of device 10 towards locations in thecenter of device 10 that are aligned with left and right eye boxes 60.Waveguides 86 may be provided with respective left and right outputcouplers 88 such as holograms formed on or in the material of waveguides86. The left and right output couplers 88 may respectively couple theleft and right images from the left and right waveguides 86 towards theleft and right eye boxes 60 for viewing by the user.

Left and right lenses 80 (sometimes referred to as outer lenses,outwardly facing lenses, or compensation bias lenses) may face outwardlytowards external objects such as real-world object 90 and away from eyeboxes 60. Opposing corresponding left and right lenses 82 (sometimesreferred to as inner lenses, inwardly facing lenses, or projection biaslenses) may face inwardly toward eye boxes 60 and away from real worldobjects such as object 90. The left-hand waveguide 86 and output coupler88 may be interposed between left lens 80 and left lens 82 and theright-hand waveguide 86 and output coupler 88 may be interposed betweenright lens 80 and right lens 82. Lenses 80 and 82 and interposedwaveguides 86 and output couplers 88 are transparent and allowreal-world image light from real-world objects such as object 90 to passto eye boxes 60 for viewing by the user. At the same time, the user canview virtual images associated with computer-generated content (left andright images) that are directed out of waveguides 86 and through lenses82 to corresponding eye boxes 60 by output couplers 88.

The strength (sometimes referred to as the power or diopter) of lenses82 can be selected to place virtual images such as illustrative virtualobject 92 at a desired distance D from device 10. For example, it may bedesirable to place computer-generated content such as text, icons,moving images, or other content at a virtual image distance D. Theplacement of virtual object 92 at distance D can be accomplished byappropriate selection of the strength of lenses 82. Lenses 82 may benegative lenses for users whose eyes do not have refraction errors. Thestrength (larger net negative power) of lenses 82 can therefore beselected to adjust distance D. For example, in a scenario in whichlenses 82 are −0.5 diopter lenses, virtual object 92 may be placed at adistance D of 2 m away from device 10. As another example, if lenses 82are −1.0 diopter lenses, virtual object 92 may be placed at a distanceof 1 m from device 10.

If desired, lenses 80 may have complementary power values (e.g.,positive powers with magnitudes that match the magnitudes of thenegative powers of lenses 82). For example, if lenses 82 have a power of−1.0 diopter, lenses 80 may have an equal and opposite power of +1.0diopter (as an example). In this type of arrangement, the positive powerof lenses 80 cancels the negative power of lenses 82. As a result, theoverall power of lenses 80 and 82 taken together will be 0 diopter. Thisallows a viewer to view real-world objects such as object 90 withoutoptical influence from lenses 80 and 82. For example, a real-worldobject located far away from device 10 (effectively at infinity), may beviewed as if lenses 80 and 82 were not present.

For a user with satisfactory uncorrected vision, this type ofcomplementary lens arrangement therefore allows virtual objects to beplaced in close proximity to the user (e.g., at a virtual image distanceD of 0.5-5 m, at least 0.1 m, at least 1 m, at least 2 m, less than 20m, less than 10 m, less than 5 m, or other suitable near-to-midrangedistance from device 10 while simultaneously allowing the user to viewreal world objects without modification by the optical components of theoptical system. For example, a real-world object located at a distanceof 2 m from device 10 (e.g., a real-world object being labeled by avirtual text label at a virtual image distance of 2 m) will opticallyappear to be located 2 m from device 10.

Some users may require vision correction. Vision correction may beprovided using tunable lenses and/or removable lenses (sometimesreferred to as supplemental lenses, vision correction lenses, removablelenses, or clip-on lenses). For example, vision correction may beprovided for a user who has astigmatism by adding a removableastigmatism correction lens to the display system of FIG. 1 . Othervision correction lenses may also be used, if desired. In general, thevision correction lenses may include lenses to correct for ammetropia(eyes with refractive errors) such as lenses to correct fornearsightedness (myopia), lenses to correct for farsightedness(hyperopia), and lenses to correct for astigmatism, prism lenses tocorrect for skewed vision, lenses to help accommodate age-relatedreductions in the range of accommodation exhibited by the eyes(sometimes referred to as presbyopia), and/or other vision disorders.

FIG. 3 is a top view of an illustrative display system for device 10. Asshown in FIG. 3 , display system 96 may include a portion of display 14(e.g., a left or right display device for providing an image to a givenone of the user's eyes that is located in eye box 60) and an associatedoptical system. The optical system may be used to route an image that isoutput by display 14 to eye box 60 while allowing a user to viewreal-world objects such as real-world object 90 that are providing areal-world image (real-world light) to eye box 60 in direction 98through lenses 80 and 82.

The optical system may include an optical coupler such as opticalcoupler 84 for coupling emitted image light into waveguide 86 from adisplay device (e.g., display 14 of FIG. 3 ), output coupler 88 forcoupling the image out of waveguide 86 in direction 100, and lenses. Thelenses may include inner lens 82 for adjusting virtual image distance Dof virtual object 92. Virtual object 92 is a visual element (sometimesreferred to as a computer-generated content or computer-generated image)that is emitted by display 14, that is coupled into waveguide 86 byoptical coupler 84, that is coupled out of waveguide 86 toward eye box60 by output coupler 88, and that passes through lens 82 in direction100 to eye box 60 for viewing by the user. The power of lens 82 may beadjusted to bring virtual object 92 closer to device 10 and the user orto place virtual object 92 at a greater distance from device 10 and theuser. Lens 80 may have a complementary power (e.g., lens 80 may be apositive lens in scenarios in which lens 82 is a negative lens) or othersuitable power to allow a user with an eye in eye box 60 to viewreal-world objects such as object 90.

To accommodate users with vision defects, one or more lenses in system96 may be removable (and therefore customizable for each user) and/ormay be tunable. Tunable lenses such as tunable liquid crystal lenses maybe dynamically adjusted by control circuitry 12 (e.g., to exhibit adesired optical power that corrects the vision of a given user).Examples of lenses that may be used in system 96 (e.g., for lens 80and/or lens 82) include fixed power lenses formed from glass, polymer,or other material (e.g., lenses that may be permanently installed insystem 96 and/or that may be temporarily installed in system 96), liquidcrystal lenses, liquid membrane lenses, geometric phase lenses, Fresnellenses, zoom lenses, catadioptric lenses, single-element lenses,multi-element lenses, and/or other lenses.

Support structures 26 in device 10 may include magnets, clips, and/orother structures that mate with lenses such as illustrative lenses 80and 82 of FIG. 3 . These support structures may include permanentmounting structures (e.g., adhesive, screws, welds, etc.) that help holdlenses 80 and/or 82 permanently in place in the housing of device 10(e.g., permanently coupled to support structures 26) and may includetemporary mounting structures such as magnets that couple tocorresponding temporary mounting structures on a removable lens. Asshown in the example of FIG. 3 , lens 80 and/or lens 82 may beremovable. For example, lens 80 may have magnets 80M that mate withcorresponding magnets 26M that are coupled to other support structures26 in device 10. Lens 82 may also have magnets 82M that mate withcorresponding magnets 26M.

If desired, lens 80 and/or lens 82 may be permanently attached tosupport structures 26. For example, lens 80 may be permanently mountedto support structure 26 and lens 82 may use magnets 82M to temporarilycouple lens 82 to corresponding magnets 26M. When it is desired tocustomize the optical system in device 10 for a given user (e.g., a userwith astigmatism), a lens 82 that corrects the given user's astigmatismmay be temporarily coupled to magnets 26M and thereby temporarilyinstalled within device 10. When a user with a different prescription(e.g., a nearsighted user with no astigmatism), a different customizedlens 82 may be removably installed within system 96 to correct for thatuser's vision defect. Lens 82 may include both a vision correctioncomponent (e.g., a negative lens component to correct for a user'snearsightedness) and a virtual image distance adjustment component(e.g., a negative lens component to place a virtual object at a desiredvirtual image distance D from device 10). Lens 80 may have a power thatcompensates for the virtual image distance adjustment component (e.g.,lens 80 may be a positive lens that is complementary to the negativelens component associated with the virtual image distance adjustment).Although shown as potentially including two lenses 80 and 82 that arefixed and/or removable, system 96 may, in general, include any suitablenumber of fixed lenses and/or removable lenses (e.g., at least twolenses where one lens is removable, at least two lenses where two lensesare removable, at least three lenses where one lens is removable or twolenses are removable, etc.). Lenses in system 96 may include singleelement lenses and/or multi-element lenses, reflective lenses, and/orother lens structures.

Lenses in system 96 may include regions of different strength. Forexample, lens 82 may be a bifocal lens, trifocal lens, progressive lens,or other lens with multiple strengths in different regions. As anexample, consider the use of a bifocal lens for implementing lens 82.The user's field of view through system 96 may be represented by thediagram of FIG. 4 . As shown in FIG. 4 , field of view 102 may bedivided into an upper portion such as upper half 102-1 and a lowerportion such as lower half 102-2. To ensure that real-world objects areviewed satisfactorily by a user with normal vision, lens 82 and lens 80may have complementary bifocal arrangements as shown in the graph ofFIG. 5 , where curve 104 represents the lens power of lens 82 as afunction of increasing vertical distance Y across lens 82 and wherecurve 104′ represents the corresponding complementary lens power of lens80 as a function of increasing vertical distance Y across lens 80. Byplacing complementary lenses 82 and 80 back-to-back as shown in FIG. 5 ,the effective lens power of the see-through optical system in system 96will be 0 diopters (no change from unobstructed vision).

At the same time, the bifocal nature of lens 82 allowscomputer-generated content to be displayed at two different virtualdistances D from device 10. As shown in FIG. 5 , lower portion 104-2 oflens 82, which covers lower half 102-2 of field of view 102 (FIG. 4 ),has larger net negative power DH, whereas upper portion 104-1 of lens82, which covers upper half 102-1 of field of view 102, has a smallernet negative power DL. With this arrangement, a virtual object in upperhalf 102-1 will be located at a farther virtual image distance D fromdevice 10 than a virtual object in lower half 102-2. This allows controlcircuitry 12 to display virtual objects at multiple different distancesD from the user.

Consider, as an example, a scenario in which the computer-generatedcontent provided by display 14 includes text labels. Control circuitry12 may, as an example, create a first label (e.g., “cup”) for a nearbyreal-world object such as a cup using a virtual object in lower half102-2 and may create a second label (e.g., “car”) for a real-worldobject such as a car that is farther away using a virtual object inupper half 102-1. Because the virtual image distance D is smaller forthe virtual object in lower half 102-2 than for the virtual object inupper half 102-1, virtual objects will appear to be at approximately thesame distance from device 10 as the real-world objects that they arelabeling. In this example, the virtual image distance of the label “cup”will appear to be the same as the distance to the real-world cup and thevirtual image distance of the label “car” will appear to be the same asthe distance to the real-world car.

Although the example of FIGS. 4 and 5 uses two different lens powerregions for lens 82 (and two complementary lens power regions for lens80), there may be any suitable number of different regions of differentpowers. For example, lenses 80 and 82 may be trifocals (see, e.g., curve104 of FIG. 6 , which represents the lens power of lens 82 in a trifocalexample, and curve 104′ of FIG. 6 , which represents the complementarylens power of lens 80) and/or may be progressive lenses (see, e.g.,curve 104 of FIG. 7 , which represents the lens power of lens 82 for aprogressive lens example in which lens power varies monotonically andcontinuously without discontinuities due to steps in lens power, andcurve 104′ of FIG. 7 , which represents the complementary lens power oflens 80). Other changes in lens power for lens 82 and for lens 80 mayalso be used, if desired (e.g., lateral changes across the horizontaldimension of lens 82, configurations with four or more different regionswith different respective lens powers, etc.).

Lenses 80 and 82 are used in imposing a lens power bias on the field ofview of the user and may therefore sometimes be referred to as biaslenses. Lens 82 serves to bias the projected computer-generated imagefrom output coupler 88 and waveguide 86 and may therefore sometimes bereferred to as a projection bias lens or projection lens, whereas lens80 serves to provide compensating bias and may therefore sometimes bereferred to as a compensation bias lens or compensation lens.

If desired, a separate removable vision correction lens can be added tosystem 96. As shown in FIG. 8 , for example, vision correction lens 106may have magnets 106M or other removable lens temporary couplingstructures that can be used to temporarily couple lens 106 to matingcoupling structures attached to support structure 26 such as matingmagnets 26M. Vision correction lens 106 may be configured to match auser's normal eyeglass prescription. For example, lens 106 may be apositive lens to correct for a user's farsightedness, a negative lens tocorrect for a user's nearsightedness, may be an asymmetric lens tocorrect for a user's astigmatism, may be a progressive lens for a userwith presbyopia, etc.

In the illustrative arrangement of FIG. 8 , lens 106, lens 82, and lens80 are removable lenses. In this type of arrangement, lens 106 may be avision correction lens that is selected on a case-by-case bases tocorrect for each user's vision, as shown in FIG. 9 and lenses 80 and 82may be replaced from time to time to adjust the virtual image distancebehavior of virtual objects presented to the user. For example, in afirst configuration for lenses 80 and 82, lenses 80 and 82 may have 1.5diopter and −1.5 diopter lens powers, respectively (to place all virtualimages at a given virtual image distance D from device 10). In a secondconfiguration for lenses 80 and 82, lenses 80 and 82 are both bifocallenses as described in connection with FIGS. 4 and 5 . In a thirdconfiguration for lenses 80 and 82, lenses 80 and 82 may be trifocals.In a fourth configuration for lenses 80 and 82, lenses 80 and 82 may becomplementary progressive lenses as described in connection with FIG. 7.

If desired, lenses 80 and 82 may be fixed lenses and lens 106 may be aremovable vision correction lens, as shown in FIG. 9 . This type ofarrangement may simplify the construction of device 10 while stillallowing a different lens 106 to be used by each different user tocustomize the optical properties of system 96 for each user (e.g., tocorrect for each different user's vision defects). Lenses 80 and 82 mayhave any suitable complementary configurations (e.g., single power,bifocal, trifocal, progressive, etc.). For example, lens 82 may be aprogressive lens as shown in FIG. 7 and lens 80 may be a complementaryprogressive lens. Users with presbyopia may use progressive eyeglassprescriptions, so, if desired, vision correction lens 106 may be aprogressive lens and/or may have a progressive lens power combined withan astigmatism correction lens component, and/or a nearsightedness orfarsightedness correction component. In general, any suitable visioncorrection lens attributes may be combined into a single removablevision correction lens such as lens 106.

If desired, the number of lens elements in system 96 may be reduced bycombining the lens properties of vision correction lens 106 into lens82, thereby creating a combined removable lens such as lens 108 of FIG.10 having magnets 108M or other removable lens coupling structures thatmate with corresponding magnets 26M in support structure 26 of device10. Lens 108 in this type of arrangement may incorporate all of thevision correction lens functions of lens 106 of FIG. 8 (e.g., a positivelens power component to correct for farsightedness, an asymmetric lenspower component for astigmatism correction, a negative lens powercomponent for nearsightedness correction, a progressive prescription tohelp with presbyopia, etc.) as well as the projection bias lensfunctions of lens 82 (e.g., a bifocal, trifocal, progressive, or othertype of projection bias lens). Lens 80 may be configured to compensatefor the lens power of the projection lens component of combinedremovable lens 108. Because lens 108 can serve as both a projection biaslens and as a vision correction lens, lens 108 may sometimes be referredto as a removable vision-correction-and-projection-bias lens.

If desired, the adjustability provided by making one or more of the lenselements of system 96 removable may, if desired, be implemented usingtunable lens components (e.g., a tunable liquid crystal lens).Arrangements in which the lens elements can be removed and replaced withdifferent lens elements to customize system 96 for different users maysometimes be described herein as an example.

In the illustrative arrangement of FIG. 11 , display 14 of device 10 isopaque. Device 10 of FIG. 11 may, if desired, include a camera tocapture images of real-world content to present on display 14 or thecamera may optionally be omitted. Device 10 may have support structures26. Display system 114 may be supported by support structures 26-2 andsupport structures 26-1 may be used to hold device 10 on a user's head.Display system 114 may include an opaque display such as display 14 ofFIG. 11 (e.g., a display that is not part of a see-through displaysystem) for displaying a computer-generated image. Display 14 may spanthe user's left and right eyes or display 14 and the other components ofFIG. 11 may be duplicated for the user's left and right eyes.

As shown in FIG. 11 , lens 110 may be used to allow a user with an eyelocated in eye box 60 to view the computer-generated image. Lens 110 maybe, for example, a catadioptric lens, a Fresnel lens, or other suitablelens (e.g., a non-removable fixed-power lens). To accommodate users withdifferent eyesight characteristics, device 10 may have a removable lenssuch as removable vision correction lens 112. Lens 112 may be removablymounted in support structure 26 using magnets 112M that temporarilycouple with corresponding magnets 26M in support structure 26.

To help improve optical performance for device 10 as a user views imageson display 14, lens 112 may have a lens power component that helpscompensate for field curvature (in addition to or in place of a lenspower component for vision correction). In particular, lens 112 may havedifferent regions with different optical powers. The optical power oflens 112 may, for example, increase at increasing radial distances fromthe center of lens 112. This type of radially progressive lens designmay spatially curve the limited accommodation of a user with presbyopiato compensate for field curvature in system 114.

An illustrative arrangement for lens 112 is shown in FIG. 12 . In theexample of FIG. 12 , there are four distinct regions 112-1, 112-2,112-3, and 112-4 (e.g., three complete or truncated ring-shaped regionssurrounding a circular region) each with a different corresponding lenspower. This illustrative arrangement has a lens power that increments insteps, but stepless configurations (e.g., progressively increasing lenspower arrangements in which lens power changes monotonically andcontinuously at increasing radial distances from central lens region112-1) may be used, if desired. Central lens region 112-1 may be locatedin the middle of lens 112 and/or may be laterally offset (e.g.,horizontally offset and shifted towards the lower portion of the user'sfield of view) to help lens 112 satisfactorily cover the user's vision(e.g., the center of lens region 112-1 may be offset from the geometriccenter of the glass member or other element forming lens 112). Visioncorrection lens attributes (e.g., a positive lens component to correctfor farsightedness, astigmatism correction, etc.) may be incorporatedinto lens 112 in combination with field curvature compensation featuresand/or lens 112 may only serve as a vision correction lens or only as afield curvature compensation lens.

FIG. 13 is a cross-sectional side view of an illustrative lens systemfor device 10 of FIG. 11 . As shown in FIG. 13 , removable lens 112 mayhave a convex anterior lens surface. Lens 110 may be a catadioptric lensand may have a concave inner surface such as concave surface 120 facingeye box 60. An air gap such as air gap 116 may separate concave surface120 of lens 110 from convex anterior lens surface 118 of removable lens112. The size of air gap 116 may be modest (e.g., less than 4 mm, lessthan 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, at least0.05 mm, or other suitable amount) to help reduce the overall size ofsystem 114. The modest size of air gap 116 may also help expand thefield of view for system 114 by allowing posterior surface 122 (e.g.,the surface of lens 112 facing eye box 60) to have enhanced curvature.If desired surface 122 and/or surface 118 may be aspheric to reduce lensastigmatism and distortion.

The following terms may sometimes be used in describing the operation ofdevice 10 and system 8.

Physical Environment

A physical environment refers to a physical world that people can senseand/or interact with without aid of electronic systems. Physicalenvironments, such as a physical park, include physical articles, suchas physical trees, physical buildings, and physical people. People candirectly sense and/or interact with the physical environment, such asthrough sight, touch, hearing, taste, and smell.

Computer-Generated Reality

In contrast, a computer-generated reality (CGR) environment refers to awholly or partially simulated environment that people sense and/orinteract with via an electronic system. In CGR, a subset of a person'sphysical motions, or representations thereof, are tracked, and, inresponse, one or more characteristics of one or more virtual objectssimulated in the CGR environment are adjusted in a manner that comportswith at least one law of physics. For example, a CGR system may detect aperson's head turning and, in response, adjust graphical content and anacoustic field presented to the person in a manner similar to how suchviews and sounds would change in a physical environment. In somesituations (e.g., for accessibility reasons), adjustments tocharacteristic(s) of virtual object(s) in a CGR environment may be madein response to representations of physical motions (e.g., vocalcommands).

A person may sense and/or interact with a CGR object using any one oftheir senses, including sight, sound, touch, taste, and smell. Forexample, a person may sense and/or interact with audio objects thatcreate 3D or spatial audio environment that provides the perception ofpoint audio sources in 3D space. In another example, audio objects mayenable audio transparency, which selectively incorporates ambient soundsfrom the physical environment with or without computer-generated audio.In some CGR environments, a person may sense and/or interact only withaudio objects.

Examples of CGR include virtual reality and mixed reality.

Virtual Reality

A virtual reality (VR) environment refers to a simulated environmentthat is designed to be based entirely on computer-generated sensoryinputs for one or more senses. A VR environment comprises a plurality ofvirtual objects with which a person may sense and/or interact. Forexample, computer-generated imagery of trees, buildings, and avatarsrepresenting people are examples of virtual objects. A person may senseand/or interact with virtual objects in the VR environment through asimulation of the person's presence within the computer-generatedenvironment, and/or through a simulation of a subset of the person'sphysical movements within the computer-generated environment.

Mixed Reality

In contrast to a VR environment, which is designed to be based entirelyon computer-generated sensory inputs, a mixed reality (MR) environmentrefers to a simulated environment that is designed to incorporatesensory inputs from the physical environment, or a representationthereof, in addition to including computer-generated sensory inputs(e.g., virtual objects). On a virtuality continuum, a mixed realityenvironment is anywhere between, but not including, a wholly physicalenvironment at one end and virtual reality environment at the other end.

In some MR environments, computer-generated sensory inputs may respondto changes in sensory inputs from the physical environment. Also, someelectronic systems for presenting an MR environment may track locationand/or orientation with respect to the physical environment to enablevirtual objects to interact with real objects (that is, physicalarticles from the physical environment or representations thereof). Forexample, a system may account for movements so that a virtual treeappears stationery with respect to the physical ground.

Examples of mixed realities include augmented reality and augmentedvirtuality.

Augmented Reality

An augmented reality (AR) environment refers to a simulated environmentin which one or more virtual objects are superimposed over a physicalenvironment, or a representation thereof. For example, an electronicsystem for presenting an AR environment may have a transparent ortranslucent display through which a person may directly view thephysical environment. The system may be configured to present virtualobjects on the transparent or translucent display, so that a person,using the system, perceives the virtual objects superimposed over thephysical environment. Alternatively, a system may have an opaque displayand one or more imaging sensors that capture images or video of thephysical environment, which are representations of the physicalenvironment. The system composites the images or video with virtualobjects, and presents the composition on the opaque display. A person,using the system, indirectly views the physical environment by way ofthe images or video of the physical environment, and perceives thevirtual objects superimposed over the physical environment. As usedherein, a video of the physical environment shown on an opaque displayis called “pass-through video,” meaning a system uses one or more imagesensor(s) to capture images of the physical environment, and uses thoseimages in presenting the AR environment on the opaque display. Furtheralternatively, a system may have a projection system that projectsvirtual objects into the physical environment, for example, as ahologram or on a physical surface, so that a person, using the system,perceives the virtual objects superimposed over the physicalenvironment.

An augmented reality environment also refers to a simulated environmentin which a representation of a physical environment is transformed bycomputer-generated sensory information. For example, in providingpass-through video, a system may transform one or more sensor images toimpose a select perspective (e.g., viewpoint) different than theperspective captured by the imaging sensors. As another example, arepresentation of a physical environment may be transformed bygraphically modifying (e.g., enlarging) portions thereof, such that themodified portion may be representative but not photorealistic versionsof the originally captured images. As a further example, arepresentation of a physical environment may be transformed bygraphically eliminating or obfuscating portions thereof.

Augmented Virtuality

An augmented virtuality (AV) environment refers to a simulatedenvironment in which a virtual or computer-generated environmentincorporates one or more sensory inputs from the physical environment.The sensory inputs may be representations of one or more characteristicsof the physical environment. For example, an AV park may have virtualtrees and virtual buildings, but people with faces photorealisticallyreproduced from images taken of physical people. As another example, avirtual object may adopt a shape or color of a physical article imagedby one or more imaging sensors. As a further example, a virtual objectmay adopt shadows consistent with the position of the sun in thephysical environment.

Hardware

There are many different types of electronic systems that enable aperson to sense and/or interact with various CGR environments. Examplesinclude head mounted systems, projection-based systems, heads-updisplays (HUDs), vehicle windshields having integrated displaycapability, windows having integrated display capability, displaysformed as lenses designed to be placed on a person's eyes (e.g., similarto contact lenses), headphones/earphones, speaker arrays, input systems(e.g., wearable or handheld controllers with or without hapticfeedback), smartphones, tablets, and desktop/laptop computers. A headmounted system may have one or more speaker(s) and an integrated opaquedisplay. Alternatively, a head mounted system may be configured toaccept an external opaque display (e.g., a smartphone). The head mountedsystem may incorporate one or more imaging sensors to capture images orvideo of the physical environment, and/or one or more microphones tocapture audio of the physical environment. Rather than an opaquedisplay, a head mounted system may have a transparent or translucentdisplay. The transparent or translucent display may have a mediumthrough which light representative of images is directed to a person'seyes. The display may utilize digital light projection, organiclight-emitting diodes (OLEDs), LEDs, micro-LEDs, liquid crystal onsilicon, laser scanning light source, or any combination of thesetechnologies. The medium may be an optical waveguide, a hologram medium,an optical combiner, an optical reflector, or any combination thereof.In one embodiment, the transparent or translucent display may beconfigured to become opaque selectively. Projection-based systems mayemploy retinal projection technology that projects graphical images ontoa person's retina. Projection systems also may be configured to projectvirtual objects into the physical environment, for example, as ahologram or on a physical surface.

As described above, one aspect of the present technology is thegathering and use of information such as sensor information. The presentdisclosure contemplates that in some instances, data may be gatheredthat includes personal information data that uniquely identifies or canbe used to contact or locate a specific person. Such personalinformation data can include demographic data, location-based data,telephone numbers, email addresses, twitter ID's, home addresses, dataor records relating to a user's health or level of fitness (e.g., vitalsigns measurements, medication information, exercise information), dateof birth, username, password, biometric information, or any otheridentifying or personal information.

The present disclosure recognizes that the use of such personalinformation, in the present technology, can be used to the benefit ofusers. For example, the personal information data can be used to delivertargeted content that is of greater interest to the user. Accordingly,use of such personal information data enables users to calculatedcontrol of the delivered content. Further, other uses for personalinformation data that benefit the user are also contemplated by thepresent disclosure. For instance, health and fitness data may be used toprovide insights into a user's general wellness, or may be used aspositive feedback to individuals using technology to pursue wellnessgoals.

The present disclosure contemplates that the entities responsible forthe collection, analysis, disclosure, transfer, storage, or other use ofsuch personal information data will comply with well-established privacypolicies and/or privacy practices. In particular, such entities shouldimplement and consistently use privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining personal information data private andsecure. Such policies should be easily accessible by users, and shouldbe updated as the collection and/or use of data changes. Personalinformation from users should be collected for legitimate and reasonableuses of the entity and not shared or sold outside of those legitimateuses. Further, such collection/sharing should occur after receiving theinformed consent of the users. Additionally, such entities shouldconsider taking any needed steps for safeguarding and securing access tosuch personal information data and ensuring that others with access tothe personal information data adhere to their privacy policies andprocedures. Further, such entities can subject themselves to evaluationby third parties to certify their adherence to widely accepted privacypolicies and practices. In addition, policies and practices should beadapted for the particular types of personal information data beingcollected and/or accessed and adapted to applicable laws and standards,including jurisdiction-specific considerations. For instance, in theUnited States, collection of or access to certain health data may begoverned by federal and/or state laws, such as the Health InsurancePortability and Accountability Act (HIPAA), whereas health data in othercountries may be subject to other regulations and policies and should behandled accordingly. Hence different privacy practices should bemaintained for different personal data types in each country.

Despite the foregoing, the present disclosure also contemplatesembodiments in which users selectively block the use of, or access to,personal information data. That is, the present disclosure contemplatesthat hardware and/or software elements can be provided to prevent orblock access to such personal information data. For example, the presenttechnology can be configured to allow users to select to “opt in” or“opt out” of participation in the collection of personal informationdata during registration for services or anytime thereafter. In anotherexample, users can select not to provide certain types of user data. Inyet another example, users can select to limit the length of timeuser-specific data is maintained. In addition to providing “opt in” and“opt out” options, the present disclosure contemplates providingnotifications relating to the access or use of personal information. Forinstance, a user may be notified upon downloading an application (“app”)that their personal information data will be accessed and then remindedagain just before personal information data is accessed by the app.

Moreover, it is the intent of the present disclosure that personalinformation data should be managed and handled in a way to minimizerisks of unintentional or unauthorized access or use. Risk can beminimized by limiting the collection of data and deleting data once itis no longer needed. In addition, and when applicable, including incertain health related applications, data de-identification can be usedto protect a user's privacy. De-identification may be facilitated, whenappropriate, by removing specific identifiers (e.g., date of birth,etc.), controlling the amount or specificity of data stored (e.g.,collecting location data at a city level rather than at an addresslevel), controlling how data is stored (e.g., aggregating data acrossusers), and/or other methods.

Therefore, although the present disclosure broadly covers use ofinformation that may include personal information data to implement oneor more various disclosed embodiments, the present disclosure alsocontemplates that the various embodiments can also be implementedwithout the need for accessing personal information data. That is, thevarious embodiments of the present technology are not renderedinoperable due to the lack of all or a portion of such personalinformation data.

The foregoing is merely illustrative and various modifications can bemade to the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A system comprising: a head-mounted supportstructure; a display coupled to the head-mounted support structure thatis configured to provide an image containing computer-generated content;and an optical system that has a first lens, a second lens, and anoptical coupler and that provides the image using the optical coupler toan eye box through the first lens while a real-world object is visiblethrough the first and second lenses from the eye box, wherein the firstlens has a vision-correction component and a projection bias component,and wherein the second lens has a compensation bias component thatcompensates for the projection bias component.
 2. The system defined inclaim 1, wherein the optical coupler is disposed between the first lensand the second lens.
 3. The system defined in claim 1, wherein thevision-correction component of the first lens is implemented using aremovable lens.
 4. The system defined in claim 3, wherein the projectionbias component of the first lens is implemented using the removablelens.
 5. The system defined in claim 3, wherein the projection biascomponent of the first lens is implemented using an additional lensdifferent from the removable lens.
 6. The system defined in claim 5,wherein the additional lens is removable.
 7. The system defined in claim5, wherein the additional lens is non-removable.
 8. The system definedin claim 3, wherein the head-mounted support structure comprises asupport structure magnet and wherein the removable lens comprises amating magnet configured to attach the removable lens to thehead-mounted support structure.
 9. The system defined in claim 8,wherein the second lens comprises a non-removable lens that ispermanently coupled to the head-mounted support structure.
 10. A systemcomprising: a head-mounted support structure; a display coupled to thehead-mounted support structure that is configured to provide an imagecontaining computer-generated content; and an optical system thatprovides the image to an eye box, wherein the optical system includesfirst and second lenses, the first lens having radially varying lenspowers and being separated from the second lens by a gap.
 11. The systemdefined in claim 10, wherein the lens powers of the first lens varyacross different radial distances from a central region of the firstlens.
 12. The system defined in claim 11, wherein the central region isoffset from a geometric center of the first lens.
 13. The system definedin claim 10, wherein the first lens is removable.
 14. The system definedin claim 13, wherein the second lens is non-removable.
 15. The systemdefined in claim 10, wherein the second lens has a fixed lens power. 16.A system comprising: a head-mounted support structure; a display coupledto the head-mounted support structure that is configured to provide animage containing computer-generated content; and an optical system thathas a removable lens, a fixed lens, and an optical coupler and thatprovides the image using the optical coupler to an eye box through theremovable lens while allowing a real-world object to be viewed throughthe removable and fixed lenses from the eye box, wherein the removablelens is configured to change a virtual distance of the image when viewedfrom the eye box.
 17. The system defined in claim 16, wherein theremovable lens has at least first and second regions with different lenspowers.
 18. The system defined in claim 17, wherein the removable lensis configured to change a virtual distance of a first portion of thecomputer-generated content based on a lens power at the first region andto change a virtual distance of a second portion of thecomputer-generated content based on a lens power at the second region.19. The system defined in claim 16, wherein the removable lens comprisesa removable lens coupling structure configured to removably couple theremovable lens to the head-mounted support structure.
 20. The systemdefined in claim 16, wherein the removable lens has a vision correctioncomponent.
 21. A system comprising: a head-mounted support structure; adisplay coupled to the head-mounted support structure that is configuredto provide a display-generated image; and an optical system that has afirst lens, a second lens, and an optical coupler, wherein the opticalcoupler provides the display-generated image to an eye box through thefirst lens while allowing a real-world object to be viewed through thefirst and second lenses from the eye box, wherein the first lens has afirst region with a first lens power that is negative and a secondregion with a second lens power, wherein the second lens has a firstregion with a first lens power that is positive and a second regionhaving a second lens power, and wherein the first region of the firstlens overlaps the first region of the second lens.
 22. The systemdefined in claim 21, wherein the second region of the first lensoverlaps the second region of the second lens, wherein the second lenspower of the first lens is negative, and wherein the second lens powerof the second lens is positive.
 23. An electronic device comprising: ahead-mounted support structure that comprises a support structuremagnet; a removable lens having a removable lens coupling structureconfigured to removably couple the removable lens to the head-mountedsupport structure, wherein the removable lens coupling structurecomprises a mating magnet configured to couple to the support structuremagnet; an opaque display that is coupled to the head-mounted supportstructure, that blocks a real-world environment from being directlyviewable from an eye box, and that is configured to provide an imagecontaining computer-generated content through the removable lens to theeye box; and a fixed lens between the removable lens and the opaquedisplay.